Speaker
Description
Symmetry enlargement occurs in correlated systems when two degenerate ordered phases breaking different symmetries combine into a super-order parameter, transforming under an enlarged algebra. While this phenomenon is in principle accompanied by the emergence of new Goldstone modes rotating between microscopically distinct orders, the exploration of such collective excitations is often not realistic in real materials. Here, we present a controlled study based on a minimal driven-dissipative platform, in which a Bose-Einstein condensate is placed at the intersection of two optical cavities, realizing two competing copies of a Z2 symmetry-breaking superradiant phase transition, alongside an enlarged O(2)-symmetric manifold. Using periodic drives that exploit dynamical symmetry reduction, we show that the emergent Goldstone mode can be harnessed to intertwine the two superradiant sectors. Furthermore, going beyond the conventional phenomenology based on Landau orders, we show the emergence of a larger class of out-of-equilibrium intertwined phases, including intertwining of purely time-crystalline orders, as well as between Landau and time crystal orders.